Synthesis of Brightly PEGylated Luminescent Magnetic Upconversion Nanophosphors for Deep Tissue and Dual MRI Imaging. Issue 1 (5th July 2013)

• Record Type: Journal Article
• Authors: Chen, Hongyu; Qi, Bin; Moore, Thomas; Colvin, Daniel C.; Crawford, Thomas; Gore, John C.; Alexis, Frank; Mefford, O. Thompson; Anker, Jeffrey N.
• Is Part Of: Small. Volume 10:Issue 1(2014:Jan.)
• Page Start: 160
• Page End: 168
• Publication Date: 2013-07-05
• Subjects: Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201300828
• Languages: English
• ISSNs: 1613-6810

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A method is developed to fabricate monodispersed biocompatible Yb/Er or Yb/Tm doped β‐NaGdF₄ upconversion phosphors using polyelectrolytes to prevent irreversible particle aggregation during conversion of the precursor, Gd₂O(CO₃)₂H₂O:Yb/Er or Yb/Tm, to β‐NaGdF₄:Yb/Er or Yb/Tm. The polyelectrolyte on the outer surface of nanophosphors also provided an amine tag for PEGylation. This method is also employed to fabricate PEGylated magnetic upconversion phosphors with Fe₃O₄ as the core and β‐NaGdF₄ as a shell. These magnetic upconversion nanophosphors have relatively high saturation magnetization (7.0 emu g⁻¹) and magnetic susceptibility (1.7 × 10⁻² emu g⁻¹ Oe⁻¹), providing them with large magnetophoretic mobilities. The magnetic properties for separation and controlled release in flow, their optical properties for cell labeling, deep tissue imaging, and their T₁‐ and T₂‐weighted magnetic resonance imaging (MRI) relaxivities are studied. The magnetic upconversion phosphors display both strong magnetophoresis, dual MRI imaging (r₁ = 2.9 mM⁻¹ s⁻¹, r₂ = 204 mM⁻¹ s⁻¹), and bright luminescence under 1 cm chicken breast tissue.</p> </abstract>